It supposed to be simple, but I must be missing something.
deletelogs file:
0 11 * * 6 ./scripts/deletelogs.sh
backupstuff file:
0 23 * * * ./scripts/backupstuff.sh
crontab -l shows the deletelogs job
If I do crontab backupstuff, then crontab -l shows the backupstuff job.
How can I schedule both, Why can't I list both with crontab -l?
The crontab file can read a set of entries from a file named on its command line:
crontab filename
or from standard input:
echo ... | crontab
Both commands replace the entire crontab.
To combine two input files:
cat file1 file2 | crontab
To add the contents of a file to an existing crontab:
( crontab -l ; cat file ) | crontab
Personally, I keep my entire crontab in a single file, installed with a simple crontab filename; I keep that file under a source control system so I can restore it if I make a mistake. But if you have a need to split it into multiple files, you can do that.
Related
I want not to save the logs that are "warning" in the log file that the crontab creates, I only want the "error" messages, does anyone know how I can exclude these messages?
I have tried doing a grep -v but it doesn't work:
45 5 * * * /home/username/barc/backupsql.sh 2>&1 | grep -v 'Warning: Using a password on the command line interface can be insecure.'
Thanks in advance for anyone trying to help me.
Crontab lets you execute 1 scheduled command/script at a time.
Piping the output of your script to Grep command won't work. Furthermore, crontab by default redirects output to dev/null, therefore you won't see the output unless you save it to a file.
I suggest something like this:
Edit your script to redirect it's output to a file with your grep command. For example by adding
DATE=$(date +"%m_%d_%Y")
some command | grep -v Warning >> /tmp/$DATE.log # Here
Edit your Cron job to execute the script every day like you did, removing everything after the pipe:
45 5 * * * /home/username/barc/backupsql.sh
In order to monitor the output you could use tail command as follows:
tail -f /tmp/$DATE.log
Im doing a Bash-Backup Script with 3 Options:
Do fullbackup
Do fullbackup at a specific time with cron
First I want to ask for the path like: Path of directory: /home
Then i want the hour for the backup: Hour for the backup (0:00-23:59) : 2:00
Then a simple question like: The backup will execute at 2:00. Do you agree(y/n)
I know how to do a crontab but I have no idea how to include that in my script so that I choose option 2 and then the script asks me for the directory and time and set then the crontab.
Any ideas or help would be appreciated!
You can get the existing crontab with
crontab -l
and install a new crontab with
crontab file
So your script would probably need something like
crontab -l | grep -v "# install-backup-script" > /tmp/file.$$
echo "$min $hour * * * /full/path/to/script # install-backup-script" >> /tmp/file.$$
crontab /tmp/file.$$
rm -f /tmp/file.$$
I have about 50 Debian Linux servers with a bad cron job:
0 * * * * ntpdate 10.20.0.1
I want to configure ntp sync with ntpd and so I need to delete this cron job. For configuring I use Ansible. I have tried to delete the cron entry with this play:
tasks:
- cron: name="ntpdate" minute="0" job="ntpdate 10.20.0.1" state=absent user="root"
Nothing happened.
Then I run this play:
tasks:
- cron: name="ntpdate" minute="0" job="ntpdate pool.ntp.org" state=present
I see new cron job in output of "crontab -l":
...
# m h dom mon dow command
0 * * * * ntpdate 10.20.0.1
#Ansible: ntpdate
0 * * * * ntpdate pool.ntp.org
but /etc/cron.d is empty! I don't understand how the Ansible cron module works.
How can I delete my manually configured cron job with Ansible's cron module?
User's crontab entries are held under /var/spool/cron/crontab/$USER, as mentioned in the crontab man page:
Crontab is the program used to install, remove or list the tables used to drive the cron(8) daemon. Each user can have their own crontab, and though these are files in /var/spool/ , they are not intended to be edited directly. For SELinux in mls mode can be even more crontabs - for each range. For more see selinux(8).
As mentioned in the man page, and the above quote, you should not be editing/using these files directly and instead should use the available crontab commands such as crontab -l to list the user's crontab entries, crontab -r to remove the user's crontab or crontab -e to edit the user's crontab entries.
To remove a crontab entry by hand you can either use crontab -r to remove all the user's crontab entries or crontab -e to edit the crontab directly.
With Ansible this can be done by using the cron module's state: absent like so:
hosts : all
tasks :
- name : remove ntpdate cron entry
cron :
name : ntpdate
state : absent
However, this relies on the comment that Ansible puts above the crontab entry that can be seen from this simple task:
hosts : all
tasks :
- name : add crontab test entry
cron :
name : crontab test
job : echo 'Testing!' > /var/log/crontest.log
state : present
Which then sets up a crontab entry that looks like:
#Ansible: crontab test
* * * * * echo Testing > /var/log/crontest.log
Unfortunately if you have crontab entries that have been set up outside of Ansible's cron module then you are going to have to take a less clean approach to tidying up your crontab entries.
For this we will simply have to throw away our user's crontab using crontab -r and we can invoke this via the shell with a play that looks something like following:
hosts : all
tasks :
- name : remove user's crontab
shell : crontab -r
We can then use further tasks to set the tasks that you wanted to keep or add that properly use Ansible's cron module.
If you have very complicated crontab entries so you can also delete it by shell module of ansible as shown in below example.
---
- name: Deleting contab entry
hosts: ecx
become: true
tasks:
- name: "decroning entry"
shell:
"crontab -l -u root |grep -v mybot |crontab -u root -"
register: cronout
- debug: msg="{{cronout.stdout_lines}}"
Explanation:- You have to just replace "mybot" string on line 8 with your unique identity of crontab entry. that's it. for "how to delete multiple crontab entries by ansible" you can use multiple strings in grep as shown below
"crontab -l -u root |grep -v 'strin1\|string2\|string3\|string4' |crontab -u root -"
I have a crontab file at /etc/crontab. I didn't place it there, it was already there, along with a lot of other files in /etc. However, when I type the command crontab -e, it creates a new file. I want it to look for crontab in /etc. This is what the command line says when I type crontab -e.
no crontab for root - using an empty one
~
~
~
~
~
"/tmp/crontab.vx7AxR" 0L, 0C
After a complete edit, this is what I end up with. Any ideas?
[root#server ~]# crontab -e
no crontab for root - using an empty one
crontab: installing new crontab
"/tmp/crontab.uJzKS0":1: bad day-of-month
errors in crontab file, can't install.
Do you want to retry the same edit?
Contents of the crontab file:
0 * * * * /var/www/html/myfile.py
Thanks, I appreciate it. I wish there was more info out there about customizing crontab.
I would like to add a crontab schedule by doing this in my server:
echo "30 * * * * /home/my/var/dir/to/script /var/etc/etc/etc/" > crontab -e
Is there a way to do this without going doing crontab -e and then typing in the command?
Could try
1)nano /etc/crontab (or any other editor, e.g. emacs)
2)echo "30 * * * * /home/my/var/dir/to/script /var/etc/etc/etc/" > /etc/crontab
3)or put the contents of this into a file, then do "file > /etc/crontab"
like root:
echo "30 * * * * /home/my/var/dir/to/script /var/etc/etc/etc/" > /var/spool/cron/crontabs/username
We have the following setup in production on RHEL:
- a custom software starting sh in init.d , which
- handles cron start , stop , reload
- writes cron tasks into separate tmp file and loads this file with crontab -e
I have been only maintaining it for several months but it works like a charm ...
The proper fix is probably to use a file as specified in https://stackoverflow.com/a/4421284/377927, but it is possible to use tee to append a line to the crontab by doing e.g.:
echo "* * * * * ls" | EDITOR="tee -a" crontab -e
tee -a will append stdin to the file it gets specfied, the EDITOR variable tells crontab to use tee -a as editor.
If you have the whole crontab in a text file, you can upload a whole crontab to replace the old crontab by doing:
cat <crontab_text_file> | crontab -
This will wipe out your old crontab. Using '-' allows you to use standard input into the crontab.